Japanese Patent Publication No. 4271086 (hereafter, Patent Literature 1; this literature corresponds to US Pre-Grant Patent Application Publication No. 2005/0282237) discloses an enzyme immunoassay method. FIG. 2 shows a sandwich method, which is included in the enzyme immunoassay method.
As shown in FIG. 2, a support 107 has an antibody 108 on its surface. The sample containing an antigen 109 is supplied to the surface of the support 107 to cause the antigen 109 to be bound specifically to the antibody 108. Subsequently, the sample containing the unreacted antigen 109 was removed from the support by washing.
Next, a labeled-antibody 111 comprising an enzyme 110 which detects the antigen 109 is supplied to the surface of the support 107 to form the complex composed of the antibody 108, the antigen 109, and the labeled-antibody 111. Subsequently, the sample containing the unreacted labeled-antibody 111 was removed by washing.
Finally, a substrate 112 of the enzyme 110 is supplied to the surface of the support 107. The enzyme 110 reacts with the substrate 112 metabolically to form a product 113. The luminescence degree or light absorption degree of the product 113 is measured so as to detect the antigen 109 indirectly.